GB1582071A - Torch with gas actuated starting rod feed device - Google Patents

Description

PATENT SPECIFICATION ( 11)

_ ( 21) Application No 38685/77 ( 22) Filed 16 Sept 1977 ( 19) 1 ( 31) Convention Application No 724 359 ( 32) Filed 17 Sept 1976 in = ( 33) United States of America (US)

00 ( 44) Complete Specification published 31 Dec 1980

MD ( 51) INT CL 3 B 23 K 7/08 _I ( 52) Index at acceptance B 3 V 4 B 2 4 C 1 582 071 MZ J O i ( 54) TORCH WITH GAS ACTUATED STARTING ROD FEED DEVICE ( 71) We, UNION CARBIDE CORPORATION, a corporation organized and existing under the laws of the State of New York, United States of America, whose registered office is 270 Park Avenue, New York, State of New York 10017, United States of America, (assignee of CLIFFORD CHARLES ANTHES and RICHARD CALVIN JONES), do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:-

This invention relates to scarfing and/or cutting torches and more particularly to a gas actuated rod feed mechanism associated with such torches for feeding a starting rod into the flame jets issuing from the torch nozzle to effect quicker starts of the scarfing or cutting operation.

Rod feed devices have been used for many years The prior art has proposed many starting rod feed devices Some devices are actuated mechanically by linkage connected to the torch lever that actuates the cutting oxygen supply Other devices are actuated by fluid pressure wherein oxygen from the main oxygen system is used as the actuating fluid.

This invention is concerned with an improved gas actuated, starting rod feed device.

United States Patent 2,433,514 discloses a gas operated starting rod feed device which this invention improves upon The Hughey device has been available since 1947 but, because of several shortcomings, mechanical systems are still used in a majority of situations This in spite of the fact that mechanical systems have a multiplicity of cams, levers and springs requiring constant adjustment and maintenance because if wear, and require considerable added force in operating torch cutting levers The added operating force of course is fatiguing and a constant source of operator complaint Previous gas operated rod feed systems, as exemplified by Hughey, have required complicated oxygen valving to supply oxygen to the rod feed mechanism and to exhaust such oxygen In addition to the valving complications, this type of system results in pressurized oxygen being present in the vicinity of the hot reaction zone during the entire scarfing or cutting operation.

This, of course, is a hazardous situation which is undesirable.

According to this invention, the necessity 55 for complicated oxygen valving is eliminated by utilizing a piston-like member actuated by a pulse of oxygen tapped from the main oxygen stream by a simple auxiliary oxygen valve arrangement The oxygen is vented 60 to atmosphere at the end of the piston stroke thereby automatically resetting the rod feed mechanism for the next cycle This feature eliminates the need for the valve arrangement of the prior art and also eliminates the 65 presence of pressurized oxygen in the vicinity of the flame during operation.

The invention will be more particularly described in conjunction with the accompanying drawings wherein; 70 Figure 1 is a front elevation view partially in section of a typical torch incorporating the rod feed mechanism of the invention; Figure 2 is a partial perspective view of the rear side of the torch body (without parts) 75 shown in Figure 1; Figure 3 is a partial view of the rear portion of the torch body showing gas passages in phantom; and Figure 4 is a side, cross sectional view of the 80 rear of the torch shown in Figure 1.

Referring now to the drawings and particularly to Figures 1 and 4, the apparatus shown therein comprises a fuel gas torch B, the gas being such as natural gas or acetylene 85 On the torch is mounted an improved starting rod feed mechanism M near the forward portion thereof to feed incremental lengths of a fusible and oxidizable metal rod R into the preheat jets discharged by the nozzle N 90 of the torch B. The torch B has a main oxygen gas passage 1 which terminates at one end in a gas nipple 3 adapted to be connected to a source of cutting oxygen A main oxygen valve 5 95 (See Figure 4) is positioned in the first gas passage 1 for permitting the flow of oxygen from the source thereof to nozzle N through the gas passage 1 The main oxygen valve 5 is connected to and operated by the torch 100 lever 7 The fuel gas enters the torch B 1,582,071 through inlet passage 9 and mixes with oxygen in mixer 11 The cutting oxygen issues in the usual way from a central orifice (not shown) in the nozzle N and the preheat jets issue from orifices surrounding the cutting oxygen orifice.

The rod feed mechanism M comprises a housing H having parallel chambers 13 and One chamber 13 has an opening 17 providing communication between second gas passage 19 and one end of said chamber 13 Remotely located from opening 17, in the wall of chamber 13, is an exhaust port 21.

Exhaust port 21 is provided with a filter 23 for preventing dust or other debris from entering chamber 13 A piston-like member is slidably located in chamber 13.

The stroke of the piston is determined by the distance from the end 26 of the piston to exhaust port 21 The stroke of the piston may be adjusted by adjusting screw member 27 or by selected pistons which are machined to provide different distances from end 26 to port 21 The end 29 of piston 25 is mechanically connected to a rod gripper 31 which is located in chamber 15 A spring member 33 is located between gripper 31 and the wall of chamber 15 for returning the gripper to its starting position at the end of a rod feed stroke A rod R is fed through a friction guide member 37 out to the flame jet end of the nozzle N by the forward movement of rod gripper 31 as the piston 25 moves forward.

The means for providing actuating gas to the opening 17 in chamber 13 includes the torch lever 7 pivotally mounted at 43 to the torch body 39 A lever arm extension 41 is pivotally secured at 43 to lever 7 A cam operator 45 is pivotally secured at 47 to lever arm extension 41 A spring member 49 is provided between cam operator 45 and lever arm extension 41 for urging said operator 45 against the wall of lever arm extension 41 A cam lever 51 is pivotally secured at 53 to the torch body 39 Cam lever 51 has an upwardly sloped ramp surface 55 on which cam operator rides when torch lever 7 is depressed Ramp surface 55 abruptly terminates in a downwardly sloped surface 57 This geometry of cam operator 45 permits the cam operator to drive the cam lever 51 into contact with the valve stem 59 of the valve 58 When cam operator 45 rides past the ramp surface the valve stem 59 immediately returns to the closed position As the torch lever continues through a normal cycle the cam operator is urged against the force of spring 49, as the torch lever is released, by the surface 57 so that the cam operator will not operate the valve stem as cam operator returns to its initial position.

The auxiliary valve member 58 is located in the torch body 39 in the gas passage 19 and includes the valve stem 59 The valve 58 is held in the body by screw members 60 and 62 These screw members permit vertical adjustment of the valve 58 to compensate for wear on valve stem 59 In operation, main oxygen is supplied to the torch B through gas nipple 3 Oxygen fills chamber 63 and passage 70 64 (see Fig 2) which is an extension of gas passage 19 As the torch lever 7 is depressed, lever arm extension 41 drives cam operator into contact with cam lever 51 Cam lever 51 contacts valve stem 59 and depresses 75 the valve stem 59 thereby permitting oxygen to flow from gas passage 64 through the valve body 65 into gas passage 19 by way of passage 66 As the cam operator 45 reaches the top of ramp surface 55 the torch 80 lever begins to open main oxygen valve 67 by gripping the stem 69 and lifting the valve body 71 so that oxygen may flow from chamber 63 into first gas passage 1 The opening of main oxygen valve 67 may be adjusted by 85 screw adjustment 73 so tha main oxygen will flow just after the pulse of oxygen is provided to the rod feed mechanism M to actuate the advance of the starting rod R.

The gas pulse provided to passage 19 is 90 introduced into chamber 13 through openings 17 and drives the piston 25 forward Piston 25 in turn drives the rod gripper 31 forward As the rod gripper 31 moves forward it grips the rod R and advances it a distance approxi 95 mately equal to the stroke of the piston 25.

At the end of the stroke the actuating oxygen is exhausted to atmosphere through exhaust port 21 Spring 33 drives the rod gripper rearwardly, which in turn returns the piston 100 to its starting position Friction guide member 37 prevents the rod from being driven in the rearward direction.

It will be noted from the foregoing detailed description that the action of the auxiliary 105 valve member 58 is such that upon release of the torch lever 7, cam operator 45 on lever arm extension 41 moves from left to right and the cam operator is rotated clockwise against the force of the spring 49 so as 110 to ride over the ramp surface 55 of cam lever 51 without opening the valve 58 This action is necessary otherwise the rod would feed on the return of the torch lever to the start position, an obviously undesirable condition 115 Operational features of the present invention over mechanical rod feed device are 1 Lower manual force required to operate torch lever; 1/2 kg vs 5 9 kg to feed rod, 3-2 kg vs 68 kg to open cutting oxygen valves, 120 and 09 kg vs 3-6 kg to hold oxygen valve wide open.

2 In line application of force to feed rod minimizes points of sliding friction, thus reducing wear and assuring positive feed of 125 rod.

3 The movement of the piston is in the same direction and parallel with the movement of the rod as it is advanced, and the centerline of the piston with respect to 130 1,582,071 centerline of the rod being fed is held to a reasonably low value of offset, both factors being instrumental in reducing friction and side thrust of forces to a minimum.

4 Reduced number of friction and wear points involved in driving rod toward nozzle, thus reducing required force to move rod and amount of wear and subsequent maintenance.

Claims (4)

WHAT WE CLAIM IS:-

1 A rod feed gas torch, comprising a torch body having a first gas passage therein providing communication between a source of gas and a torch nozzle mounted at one end of said torch body, and a starting rod feed mechanism mounted on said torch body and comprising: a housing, a piston in said housing, a rod gripper connected to said piston for parallel movement therewith; means for returning the rod gripper, and thus the piston, to their respective start positions; a second gas passage providing communication between one side of said piston and said first gas passage; valve means located in said second gas passage for providing a pulse of gas to said piston, said valve means having a valve stem for opening the valve of said valve means; wherein the housing has an exhaust port, the piston in said housing seals said exhaust port, and means are provided for operating said valve means in one direction only, including a torch lever pivotally mounted to the torch body, a lever arm extension pivotally mounted to said torch lever; a cam operator pivotally and resiliently mounted at one end of said lever arm extension; a cam lever pivotally mounted to the torch body and in operable relationship to said cam operator so that only when said torch lever is depressed is the cam operator caused to drive the cam lever into contact with said valve stem causing a pulse of gas to flow through said second gas passage to one side of said piston thereby driving said piston until said exhaust port is opened whereupon said pulse of gas is exhausted to atmosphere so that the rod gripper advances the starting rod a distance equal to the stroke of the piston and the rod gripper is then reset by said means for another stroke.

2 A torch according to claim 1, wherein said cam lever has an upwardly sloped ramp surface on which the cam operator rides when the torch lever is depressed to drive the cam lever into contact with said valve stem, said ramp surface abruptly terminating in a downward sloped surface so that the resiliently mounted cam operator will permit the cam lever to release the valve stem thereby immediately closing the valve means and so that on the return stroke the resiliently mounted cam operator will rotate upon contacting the down wardly sloped surface so as to prevent opening of the valve means on said return stroke.

3 A torch according to claim 1 or 2, wherein the rod feed housing provides substantially parallel chambers; the rod gripper being located in one chamber, and the piston being located in the other chamber and mechanically connected to said rod gripper, said other chamber having an exhaust port sealed by said piston when said piston is in its starting position to determine by its location the stroke of the piston.

4 A torch according to claim 3, wherein said rod gripper return means comprises a resilient member disposed in said one chamber between said rod gripper and said chamber wall to drive said rod gripper to its starting position when said gas is exhausted to atmosphere.

A rod feed gas torch substantially as hereinbefore described with reference to the accompanying drawings.

W P THOMPSON & CO, Coopers Building, Church Street, Liverpool Ll 3 AB.

Chartered Patent Agents.

Printed for Her Majesty's Stationery Office by Burgess & Son (Abingdon), Ltd -1980.

Published at The Patent Office, 25 Southampton Buildings, London, WC 2 A l AY, from which copies may be obtained.